Microfilm reader printer

ABSTRACT

This invention is a low-cost microfilm reader printer which uses sheet form print material. The invention utilizes a sheet-feeding mechanism having a compressible dispensing roll in contact with one end of a stack of sheet print material, and a guide-disposed adjacent the periphery of the roller. When rotated, the dispensing roller separates sheet in the stack and feeds successive sheets between the roller and the guide approximately 180* around the roller and directs the dispensed sheet to an exposure station above and parallel to the storage area. Subsequent to exposure, the exposed sheet is advanced to a developer.

United States Patent inventors Appl. No.

Filed Patented Assignee Wolodymyr Diachuk Columbia Heights;

Thomas A. Turgeon, Minneapolis. both oi Minn.

Mar. 24. 1969 Nov. 9, 197i Minnesota Mining and Manufacturing Company St. Paul. Minn.

MICROFILM READER PRINTER 13 Claims, 6 Drawing Figs.

U.S. Cl 355/45 355/5l. 355/57. 355/65 Int. Cl .j. G03b 27/70 Field of Search 355/27. 44

(56] References Cited UNITED STATES PATENTS 3.308.7l3 3/l967 Miller. 355/27 X 3,343,450 9/l967 Glaser et al 355/5l 3.389.635 6/1968 Teutsch 355/66 3.424.526 H1969 Sacre 355/66 X 3.432.234 3/1969 Johnson i. 355/44 X Primary Examiner-Samuel S. Matthews Assislun! Examiner-Richard A. Wintercorn Allorney-Kinney. Alexander. Sell. Steldt & Delahunt ABSTRACT: This invention is a low-cost microfilm reader printer which uses sheet form print material. The invention utilizes a sheet-feeding mechanism having a compressible dispensing roll in contact with one end ofa stack of sheet print material. and a guide-disposed adjacent the periphery of the roller. When rotated. the dispensing roller separates sheet in the stack and feeds successive sheets between the roller and the guide approximately l80 around the roller and directs the dispensed sheet to an exposure station above and parallel to the storage area. Subsequent to exposure. the exposed sheet is advanced to a developer.

PATENTEUHUV 9 |97| SHEET 1 [IF 2 l N VEN TOR. oMAs A. TURGEON W01. 00 YM we D/A CHUK I M AT TORNE Y6 MICROFILM READER PRINTER This invention relates to microfilm reader printers and in one aspect to a simplified sheet-storing, feeding and handling apparatus affording in a microfilm reader printer a more economical unit.

Microfilm reader printers are well known in the art. It is also well known that the reader printers utilize optical systems for the projection of a light image onto a heat-developable, lightsensitive sheet material to produce a visible enlarged print of the microfilm image. These machines, however, have utilized rolls of the sensitized material, which material is advanced from the roll and positioned across a support defining a focal plane. The exposed web material is subsequently advanced past a cutting device toward the developing unit wherein a severed length from the web is processed or developed and delivered from the machine.

The drive mechanism for the rolls, the severing mechanism to produce this result required costly parts because of the precision necessary on the parts to assure the proper feeding and steering of the web from the supply roll to the focal plane, for steering and driving the web from the focal plane past the severing means, and for feeding the severed sheet to the developer.

Applicant's have substituted a sheet-feeding system for the web-feeding and cutting system of the prior art devices. More particularly however they have developed a novel sheet-feeding mechanism to substitute for the web-feeding mechanism which sheet-feeding mechanism is simplified, accurate, requires no elaborate drive system, and combines with the sheet-feeding mechanism the sheet drive and sheet support at a focal plane to afford exposure thereof for the production of a copy of the light image from the microfilm.

The present invention comprises a microfilm reader printer having a light source, a support for microfilm, a projection system, a rear projection screen, mirrors for directing an image onto said screen, a support for a supply of sensitized material, means defining an exposure plane, a developing unit for developing said sensitized material, and means for advancing the sensitized material to said exposure plane from said supply, wherein said support for a supply comprises a support for a stack of sheet material and wherein said means for advancing the sensitized material to said exposure plane affords the sequential feeding and separation of the uppermost sheet in a stack. The sheet-dispensing mechanism comprises a pivotal support for a stack of sheet material, a foam-covered dispensing roll positioned for engagement with the uppermost sheet in a said stack, and guide means directing a dispensed and separated sheet to a position above the stack upon rotation of said dispensing roll.

The invention will be more fully understood after reading the following description which refers to the accompanying drawing wherein:

FIG. 1 is a schematic vertical sectional view of a microfilm reader printer constructed in accordance with the present invention;

FIG. 2 is a perspective view of the sheet-dispensing mechanism of the reader printer of FIG. 1 with the sheet-guiding and supporting elements removed;

FIG. 3 is an enlarged fragmentary sectional view illustrating the separating elements of the sheet-dispensing mechanism;

FIG. 4 is a vertical sectional view of the sheet-dispensing mechanism in one operating position thereof;

FIG. 5 is a vertical sectional view of the sheet-dispensing mechanism in a second operating position; and

FIG. 6 is an enlarged fragmentary sectional view illustrating a second embodiment of the sheet-separating and feeding mechanism.

Referring now to the drawings there is illustrated in FIG. 1 a microfilm reader printer affording the user an opportunity to view on a rear projection screen 10 light images generated by a source of illumination 11 and a microfilm positioned on a support 12. The light image is focused by a projection lens mounted in a floating lens barrel 14 which directs the image from the film to a first reflecting element or mirror 16 onto a movably mounted reflecting element or second mirror 17, which directs it to the rear of the screen 10.

When it is desired to produce a visible copy of the light image or make an enlarged print of the graphic information on the microfilm, the operator displaces the second mirror 17 from the normal position shown in solid lines in FIG. I to the position shown in dotted lines. This defines a second light path directing the light image from the microfilm to the first reflecting means and from there onto a support plate 20. The support plate 20 constitutes one member of a copy-sheet-dispensing mechanism 21 which supports a sheet of sensitized material in a position to receive and be exposed by said light image. After exposure, the sensitized sheet is advanced to a developer or processing unit 22 wherein the light image is developed to a visible form on the copy sheet and the copy sheet is dispensed from a chute 24 in the forward end of the unit.

In the normal position of the unit with the mirror 17 in position as shown in solid lines in FIG. I, an on off switch is operable to energize a lamp 25 in the light source 11, which lamp 25 is connected in series with a switch 26 mounted on one end of a guide support 27. The support 27 forms a guide for a carriage 28 to which the mirror 17 is pivotally connected at an axis 29. Drive means are provided for moving the carriage along the guide 27, and as illustrated, the drive means takes the form of a manually operable arm 30 extending from the carriage 28 forwardly out of the reader printer where it terminates in a handle 31. Thus when it is desired to make a print the operator grasps the handle 3], pulling the same from the solid-line position to the dotted-line position, moving the carriage 28 along the guide 27, opening the switch 26 and extinguishing the light source 11. As the lower portion of the mirror 17, as illustrated in FIG. 1, engages a fixed-stop member 32 having a cam face 34, the mirror 17 is pivoted about the axis 29 to the vertical dotted-line position as shown. In this position the carriage 28 engages a normally open third switch 35 which is connnected to the lamp 25. Closing the switch 35 directs current to the lamp 25 in the light source 11 through a suitable timer (not shown) in series therewith. When the timer has operated it opens the circuit to the lamp through switch 35 and the lamp is extinguished. Thus the image from the microfilm has been suitably directed onto the focal plane or support 20 to expose a sheet of sensitized material thereon. An indicator will indicate to the operator that the exposure is completed and he can again grasp the handle 31, moving the same from the dotted-line position to the solid-line position, returning the carriage 28 to the position closing the switch 26.

Movement of the carriage 28 along the guide 27 not only moves the mirror 17 out of the light path, permitting exposure of the sensitized sheet but also transmits a driving force through a cable 36 to the sheet-dispensing mechanism 21.

The sheet-dispensing mechanism 21 comprises a frame having transversely spaced parallel sidewalls 40 and 41. Extending transversely and positioned between the sidewalls is a pivotally mounted receptacle or support member 44 for receiving and supporting a stack 38 of sensitized sheet material. The support member 44 is pivoted at one end between the sidewalls 40 and 41 on pins 45, one of which is shown in FIGS. 4 and 5, for movement about an axis parallel to the axis of shaft 49. The stack of sheet material may be supplied in a package or box adapted to be received by the support member 44. The support member 44 has a top wall, bottom wall, transversely spaced sidewalls, and an end wall, which end wall is adjacent the pivot pins 45. The top wall of the support member 44 is formed adjacent one end with spaced cutaway corner portions exposing the sheet material in the stack 38.

Extending transversely of the frame and joumaled in the sidewalls 40 and 41 is a shaft 49. The shaft 49 supports a pair of foam-covered sheet-dispensing rollers 50 and 51 which are secured thereto for rotation with the shaft 49. At one end the shaft 49 extends beyond the side wall 41 and is connected to a one-way clutch 52. As is conventional, one-half of the clutch 52 is secured to the shaft 49 and the other end is secured to a drive member such as the pulley 54 with the two halves biased into engagement by a spring.

Extending also between the sidewalls 40 and 41 is a fixed rod 55 carrying a cable pulley 56. Positioned around the pulley 56 and secured at one end to the top wall of the support member 44 is a cable 57 having at its other end a tension spring 58. The other end of the spring 58 is connected by a cable 59 to an eccentric hub 60 which is mounted on a second transversely extending rotatable shaft 61 forming part of a drive means for the sheet-dispensing mechanism 21.

The rotatable shaft 61 is joumaled in the sidewalls 40 and 41 and carries a pulley at each end thereof. A first pulley 62 receives the drive cable 36 which is secured to the carriage 28 for driving the sheet-dispensing mechanism 21. A pulley 64 positioned at the other end of the shaft 61 drives a cable 65 wrapped around said pulley 64 and around the pulley 54 to drive the shaft 49 through the one-way clutch 52.

The shaft 61 has a pair of transversely spaced foam-covered sheet-feeding rollers 66 and 67 fixed thereto between the walls 40 and 41. Positioned adjacent the inner face of each of these sheet-feeding rollers 66 and 67 is a radially extending cam 69 which is fixed to the shaft 61.

Positioned over the shafts 49 and 61 is a paper guide frame which includes the support plate 20 which defines the focal plane and which supports the sensitive paper. This paper guide frame is mounted for pivotal movement about the axis of the shaft 49 and extends across the frame terminating above the sheet developer or processor 22. The paper support plate 20 has, at one end above the shaft 49, a deflected end which extends radially inwardly of the outer peripheral surface of the rollers 50 and 51. Directly above each of the rollers 66 and 67 is an opening in the support plate 20 permitting the periphery of the rollers 66 and 67 to reach a piece of sheet material positioned thereon. The openings do not however extend to a position above the earns 69. At the opposite end the support plate 20 is formed with a 90 bend for directing the exposed sheet material to the process or 22.

Positioned in spaced relation above the support plate 20 and defining a portion of the guide frame is a plate 74. The plate 74 at one end is formed with an arcuate end portion 75 forming a guide about the rollers 50 and 51 which contacts the outer periphery of the rollers, or is closely spaced therefrom at areas between 90 and l80 about their periphery to afford continued driving force on a sheet of material. In FIG. 3, the curve in the end portion 75 substantially corresponds to the periphery of the rollers 50 and 51 and is positioned about said rollers. The center portion of the planar surface of the plate 74 above the major portion of the plate 20 is formed with an enlarged rectangular opening 76 exposing therethrough the plate 20 or a piece of sheet material positioned thereon. The opening 76 is formed at the forward end of the unit with a flange 77 to guide the leading edge of the sheet material between the plates 74 and 20. The forward end of the opening 76 terminates substantially directly above the axis of the shaft 61. The forward end of plate 74 maintains a spaced relationship with plate 20 by suitable spacers and is formed with a bend directing the copy sheet into the processor 22.

In the embodiment illustrated in FIGS. 1 through 5, the sheets in the stack are fed singly and successively from the stack. To accomplish this easily, inexpensively and reliably, there is positioned, parallel to and adjacent the shaft 49, a rod 79 adjustably secured to the walls 40 and 41. The rod 79 carries a pair of separating elements 80 and 81, each of which has a convex surface. disposed adjacent the periphery of one of the rollers 50 and 51, respectively. The shaft 49 and the separating elements 80 and 81 are disposed to be adjacent one end of the stack of sheet material 38.

Referring now to FIG. 3 there is illustrated the operation of the dispensing rollers 50 and 51 and the short separating elements 80 and 81. As shown the dispensing roll 50 is positioned above one end of the stack of sheet material supported in the support 44. Rotation of the roller 50 in the clockwise direction as viewed in FIG. 3 causes an upper sheet 82 of the stack 38 to be driven by the foam coating on the roll 50 toward the separating element 80. Because of the friction between the sheets the second sheet 83, and others, may possibly be advanced along with the upper sheet 82 as illustrated. The separating element has its upper convex surface in contact with the periphery of the surface of the roll 50 and preferably the separating element 80 slightly compresses the dispensing roll 50. As the roll 50 advances the sheet 82 and possibly the sheet 83 the sheets contact the separating element 80. The peripheral surface of the roll 50 has a high coefficient of friction with the sheet material, so that when the roll 50 is placed in contact with the stack of sheet material 38 and rotated, the roll 50 will readily feed the sheet 82 from the stack 38. The separating element 80 has a coefficient of friction with the sheet material which is less than that between the surface on the roll 50 and the sheet material but greater than the coefficient of friction between the sheet 82 second and the sheet 83 such that the sheets 82 and 83 are separated when the sheet 83 contacts the stationary separating element 80. Because with respect to the sheet material the roll 50 has a higher coeffcient of friction than has the separating element 80 the upper sheet 82 will be moved by the roll 50 over the element 80 and the coating on the roller 50 will be compressed to move the sheet 82 between the roller 50 and the separating element 80 and into the arcuate portion 75 of the guide plate 74. The guide 74 provides a restricted path for the sheet, positioning the same upon the plate 20 at the focal plane as the roller 50 continues to rotate and drives the sheet 82 through the guide.

In operation, the reader printer is in its normal position as shown in FIG. I with the sheet-material-supporting member 44 of the sheet-dispensing mechanism 21 in the position shown in FIG. 4. In this position, the spring 58 is extended and under tension, raising the sheet material support member 44 and the stack of sheet material 38 into firm frictional contact with the periphery of the rollers 50 and 51. When the user has located and centered a microfilm image in the optic axis of the projection system the same will be centered on the rear projection screen 10 for his visual inspection. If a print is desired he grasps the handle 31 and draws the carriage 28 forwardopening switch 26 cutting off the power to the lamp 25. On moving the carriage 28 forward along the guide 27 he is pulling on the cable 36 to rotate the pulley 62 in a counterclockwise direction as viewed in FIGS. 1 and 2, thereby driving the pulley 64 in a counterclockwise direction and the pulley 54 in a clockwise direction. In this direction of movement the clutch 52 is driving the shaft 49 and the rollers 50 and 51 are rotating in a clockwise direction as shown in FIGS. 4 and 5, moving the uppermost sheet 82 from the stack 38 into the guide 75. The rotation of the pulley 62 in a counterclockwise direction is rotating the shaft 61 and the hub 60 in a counterclockwise direction relieving tension on the spring 58 causing it to contract after a predetermined angular movement of the sheet-dispensing rolls 50 and 51 and of the hub 60. After the spring 58 contracts the stack of sheet material 38 and support 44 are moved away from the dispensing rolls 50 and 51 to the position shown in FIG. 5. This will not happen however prior to the upper sheet being driven and separated from the stack 38 and moved into the guide where the paper is held against the arcuate portion 75 by the rollers 50 and 51 to be driven between the plate 74 and the plate 20. As the carriage 28 approaches the forward end of the guide 27 and mirror 17 is tilted to a position generally normal to the guide 27 as illustrated by the dotted lines. Also in this position the cams 69 have turned approximately 360 such that the cam strikes the undersurface of the plate 20 raising the guide member allowing the forward edge of the sheet 82 to be advanced from the upper tangential edge of the rollers 50 and 51 to a position above the upper tangent point of the feed rollers 66 and 67. The spacing between the axis of the rollers 50 and 51 and the axis of the rollers 66 and 67 is shorter than the length of the sheet material. The sheet is now in position generally parallel and coextensive or in overlying position to the support 44 and continued movement by the roller 50 does not move the trailing edge of the sheet beyond the tangent point of the roller 50, and the cam 69 moves from beneath the frame 20 allowing the leading edge of the sheet material between the plate 74 and the upper portions of the rollers 66 and 67. The carriage 28 also closes the switch 35 energizing the lamp 25 in the light source, energizing the timer and projecting an image onto the sheet material on the focal plane defined by the support plate 20. When the time on the timer has expired the lamp 25 is extinguished and an indicator advises the operator of the same. The operator may then return the handle 31 to the normal position. In doing this the carriage 28 moves the cable 36 in the opposite direction driving pulley 62 and pulley 64 clockwise as well as the rollers 66 and 67 such that the sheet is advanced from between the plates 20 and 74 into the processing unit 22. The dispensing rolls 50 and 51 are not rotated as the one-way clutch 52 is slipping.

The processing unit 22 is a mangle heat-developing unit having a preset thermostat and which comprises a floating heater shoe 84 biased against a soft-surfaced roller 85 which is rotated by an electric motor (not shown). This roller 85 is rotated continuously and the heater is operated continuously when the reader printer is on. Along one side of the roller 85, where the sheet material is directed from the plates 20 and 74, is an entrance opening, and the roller will advance the sheet around the heated shoe to develop the sheet material. As the sheet leaves the nip between the roller and the shoe the sheet is directed by guide members 86 and 87 into the exit chute 24.

As the rollers 66 and 67 drive the sheet to the processor 22 the roller 85 picks it up. To prevent wrinkling the cams 69 again move under the plate 20 raising the same to free the sheet material from a driving force therefrom, after the predetermined length is fed to the processor to be picked up thereby.

The rollers 50, 51, 66 and 67 are preferably covered with about is inch (0.3 cm.) of polyester foam. One example of such material is a soft, closed-cell polyester foam having an open pore irregular surface with a density of pounds per cubic foot and available as "Polymer 6060" from Corcoran Manufacturing Company, Inc., of Long Beach, Calif. 90804, U.S.A.

The separating elements 80 and 81 are formed of an elastomer, for example, a urethane of about 80 durometer, and they are preferably formed by extrusion to afford a glossy surface. This material is available as Compound No. 531 80A from Maco Industries, Inc., Chicago, Illinois, U.S.A.

Referring now to FIG. 6, there is illustrated a sheetdispensing device having a fixed (except when loading) support member 90 for a stack 91 of sheet material. Positioned above one end of the stack of sheet material is a shaft 92 supporting thereon spaced dispensing rolls 93. The rolls 93 may, for example, have an outer tire or covering about it inch thick (1.9 cm.) of a low-density closed-cell foam, e.g., 4 pounds per cubic foot polyester urethane, which is resilient and compressible. Positioned about the roll 93 is an arcuate guide member 94 which contacts the roll 93 at points thereabout between 90 and 180 to cooperate with said rolls for guiding and driving successive sheets of sensitized material between guide plates 95 and 96. The fixed position of the support 90 and the shaft 92 remain constant but the resilience and compressibility of the foam coating maintains the outer surface of the roll in contact with the uppermost sheet in the stack to feed the same off the stack and around the guide 94. The shaft 92 would be driven in only one direction as shaft 49 was in the device of FIG. 3. Separation of the sheets is afforded by piercing the stack of sheet material at the opposite end of the stack with a thin pin 98. A tiny hole may be drilled in the stack to receive the pin. As the roll 93 drives the upper sheet it will be torn from the pin but the pin holds the remaining sheets in the stack.

What is claimed is:

I. A copy-sheet-dispensing mechanism comprising support means for supporting a stack of sheet material,

a rotatable resilient compressible foam-covered dispensing roll disposed adjacent one end of said support means to be positioned in contact with one end of a single sheet of a stack of sheet material, and

a guide member disposed around and contacting said dispensing roll in circumferentially spaced locations for directing each sheet as it is drawn off said stack around said dispensing roll to a position generally parallel with said support means.

2. A copy-sheet-dispensing mechanism according to claim I wherein said dispensing roll is compressible to accommodate a stack of sheet material and wherein the axis of said dispensing roll is fixed relative to said support means during operation of said mechanism to successively feed sheets from a said stack singly to said guide member.

3. A copy-sheet-dispensing mechanism according to claim ll wherein said support means is pivotally mounted for movement relative to said dispensing roll and said mechanism comprises means for drawing said support means toward said dispensing roll and for moving said support means away from said dispensing roll after rotation thereof through a predetermined arcuate extent.

4. A dispensing mechanism of claim 1 wherein said guide member has an arcuate path substantially identical that of said dispensing roll and is in contact with said roll.

5. A copy-sheet-dispensing mechanism comprising support means supporting a stack of sheet material,

a rotatable foam-covered dispensing roll disposed adjacent one end of said support means to be positioned for engagement with a single sheet of material in said stack adjacent one end thereof, said dispensing roll having a high coefficient of friction with said sheet material to afford movement of a said sheet upon rotation thereof, separating element positioned adjacent said one end of said support means to be adjacent said one end of a said stack, said separating element having a convex surface in adjacent position to the periphery of said dispensing roll with the axis of said convex surface being generally parallel to the axis of said dispensing roll, said separating element having a coefficient of friction with said sheet material less than that of said dispensing roll with said sheet material and which exceeds the coefficient of friction between individual sheets of said sheet material to be fed,

whereby said dispensing roll may drive one or more sheets of material off a said stack toward said separating element and upon contact of said sheets other than said single sheet with said element, the sheets will be separated permitting only the single sheet to pass between said dispensing roll and said separating element.

6. A sheet-dispensing mechanism according to claim 5 wherein guide means is disposed in contact with said dispensing roll for guiding a said sheet separated from said stack around said dispensing roll, and said guide means defines a sheet support positioned generally parallel to said support means such that a said sheet driven from said stack is moved to a position generally parallel to said stack.

7. A sheet-dispensing mechanism according to claim 5 wherein said support means is pivotally mounted for movement on an axis parallel to the axis of said dispensing roll and said separating element, and means are provided for moving said support means toward said dispensing roll when a sheet from a said stack is to be separated therefrom.

8. A sheet-dispensing mechanism according to claim 7 wherein drive means is provided for driving said dispensing roll in one direction, said drive means including means for moving said support means in a direction away from said dispensing roll upon rotation thereof to a predetermined extent in said one direction.

9. A sheet-dispensing mechanism according to claim 6 wherein said guide member comprises spaced plates to position a sheet therebetween and a feeding roll spaced from said dispensing roll for movement through an opening in one of said plates to contact a said sheet and feed the same from between said plates.

10. A microfilm reader comprising a light source, a support for a microfilm, means for directing said light through said microfilm and for projecting a light image therefrom, a rear projection screen for viewing a said image means defining an exposure plane for positioning sensitized material to be exposed by a said light image, means for supporting a supply of sensitized sheet material, means for separating and feeding individual sheets of said material from said supply to said exposure plane to be exposed to said light image, and processor means for developing said sensitized sheet material, wherein said means for supporting said sensitized sheet material is a receptacle for a stack of said sheet material positioned generally parallel with said exposure plane, and wherein said means for separating and feeding said sheet material comprises:

a dispensing roll positioned for contact with a single sheet adjacent one end of said stack of sheet material; and a guide member disposed around and contacting said dispensing roll in circumferentially spaced locations for directing each sheet as it is drawn off said stack around approximately one-half the periphery of said dispensing roll to said exposure plane.

11. A reader printer according to claim 10 wherein said means defining said exposure plane comprises guide plates positioned in substantially parallel position to and superimposed relative to said receptacle, and wherein said dispensing roll is positioned adjacent one end of said receptacle and a said stack and adjacent one end of said exposure plane, and said guide member is arcuate and cooperates with said dispensing roll for driving a sheet from a said stack and onto said exposure plane, whereby the sheet from the stack is inverted to place the sensitized coating of the sheet material in an exposed position and using an uncoated side to be contacted by said dispensing roll.

12. A reader printer as defined in claim 10 wherein said rear projection screen is at least 8 inches by 8 inches and said sheet material is at least 8 inches by 8 inches, and wherein said dispensing roll is formed of a closed cellular polymeric-foam material with an open-pore irregular surface.

13. A reader printer as defined in claim 11 further comprising a movable reflector having a first position for directing said light image to said rear projection screen and a second position permitting said light image to be directed to said exposure plane, manually operated means connected to said reflector for moving the same from sa d first position to said second position and back to said first position, drive means for said dispensing roll, said drive means being operated by said manually operated means when moving said reflector to said second position to drive a sheet.

t i a t 

1. A copy-sheet-dispensing mechanism comprising support means for supporting a stack of sheet material, a rotatable resilient compressible foam-covered dispensing roll disposed adjacent one end of said support means to be positioned in contact with one end of a single sheet of a stack of sheet material, and a guide member disposed around and contacting said dispensing roll in circumferentially spaced locations for directing each sheet as it is drawn off said stack around said dispensing roll to a position generally parallel with said support means.
 2. A copy-sheet-dispensing mechanism according to claim 1 wherein said dispensing roll is compressible to accommodate a stack of sheet material and wherein the axis of said dispensing roll is fixed relative to said support means during operation of said mechanism to successively feed sheets from a said stack singly to said guide member.
 3. A copy-sheet-dispensing mechanism according to claim -1 wherein said support means is pivotally mounted for movement relative to said dispensing roll and said mechanism comprises means for drawing said support means toward said dispensing roll and for moving said support means away from Said dispensing roll after rotation thereof through a predetermined arcuate extent.
 4. A dispensing mechanism of claim 1 wherein said guide member has an arcuate path substantially identical that of said dispensing roll and is in contact with said roll.
 5. A copy-sheet-dispensing mechanism comprising support means supporting a stack of sheet material, a rotatable foam-covered dispensing roll disposed adjacent one end of said support means to be positioned for engagement with a single sheet of material in said stack adjacent one end thereof, said dispensing roll having a high coefficient of friction with said sheet material to afford movement of a said sheet upon rotation thereof, a separating element positioned adjacent said one end of said support means to be adjacent said one end of a said stack, said separating element having a convex surface in adjacent position to the periphery of said dispensing roll with the axis of said convex surface being generally parallel to the axis of said dispensing roll, said separating element having a coefficient of friction with said sheet material less than that of said dispensing roll with said sheet material and which exceeds the coefficient of friction between individual sheets of said sheet material to be fed, whereby said dispensing roll may drive one or more sheets of material off a said stack toward said separating element and upon contact of said sheets other than said single sheet with said element, the sheets will be separated permitting only the single sheet to pass between said dispensing roll and said separating element.
 6. A sheet-dispensing mechanism according to claim 5 wherein guide means is disposed in contact with said dispensing roll for guiding a said sheet separated from said stack around said dispensing roll, and said guide means defines a sheet support positioned generally parallel to said support means such that a said sheet driven from said stack is moved to a position generally parallel to said stack.
 7. A sheet-dispensing mechanism according to claim 5 wherein said support means is pivotally mounted for movement on an axis parallel to the axis of said dispensing roll and said separating element, and means are provided for moving said support means toward said dispensing roll when a sheet from a said stack is to be separated therefrom.
 8. A sheet-dispensing mechanism according to claim 7 wherein drive means is provided for driving said dispensing roll in one direction, said drive means including means for moving said support means in a direction away from said dispensing roll upon rotation thereof to a predetermined extent in said one direction.
 9. A sheet-dispensing mechanism according to claim 6 wherein said guide member comprises spaced plates to position a sheet therebetween and a feeding roll spaced from said dispensing roll for movement through an opening in one of said plates to contact a said sheet and feed the same from between said plates.
 10. A microfilm reader comprising a light source, a support for a microfilm, means for directing said light through said microfilm and for projecting a light image therefrom, a rear projection screen for viewing a said image means defining an exposure plane for positioning sensitized material to be exposed by a said light image, means for supporting a supply of sensitized sheet material, means for separating and feeding individual sheets of said material from said supply to said exposure plane to be exposed to said light image, and processor means for developing said sensitized sheet material, wherein said means for supporting said sensitized sheet material is a receptacle for a stack of said sheet material positioned generally parallel with said exposure plane, and wherein said means for separating and feeding said sheet material comprises: a dispensing roll positioned for contact with a single sheet adjacent one end of said stack of sheet material; and a guide member disposed around and contacting said dispensing roll in cirCumferentially spaced locations for directing each sheet as it is drawn off said stack around approximately one-half the periphery of said dispensing roll to said exposure plane.
 11. A reader printer according to claim 10 wherein said means defining said exposure plane comprises guide plates positioned in substantially parallel position to and superimposed relative to said receptacle, and wherein said dispensing roll is positioned adjacent one end of said receptacle and a said stack and adjacent one end of said exposure plane, and said guide member is arcuate and cooperates with said dispensing roll for driving a sheet from a said stack and onto said exposure plane, whereby the sheet from the stack is inverted to place the sensitized coating of the sheet material in an exposed position and using an uncoated side to be contacted by said dispensing roll.
 12. A reader printer as defined in claim 10 wherein said rear projection screen is at least 8 inches by 8 inches and said sheet material is at least 8 inches by 8 inches, and wherein said dispensing roll is formed of a closed cellular polymeric-foam material with an open-pore irregular surface.
 13. A reader printer as defined in claim 11 further comprising a movable reflector having a first position for directing said light image to said rear projection screen and a second position permitting said light image to be directed to said exposure plane, manually operated means connected to said reflector for moving the same from said first position to said second position and back to said first position, drive means for said dispensing roll, said drive means being operated by said manually operated means when moving said reflector to said second position to drive a sheet. 